High blood pressure can occur in pregnancy in two forms. It may be a preexisting condition, called chronic hypertension, or it can develop during pregnancy--a condition known as gestational hypertension. It is also called toxemia or preeclampsia and occurs most often in young women with a first pregnancy.
AC relays. AC relays are manufactured similar to their DC counterparts. If AC current is applied to a DC relay, the relay will pulse at the frequency of the AC current. To overcome this problem, the core is equipped with a shading ring on one-half of the core (Photo 2).
So to ensure that it's able to get the power it needs consistently, the fan needs to be paired up with an A/C Fan Relay. This device is what your air conditioning system uses to establish control over the flow of electric current coursing through its fan. The moment the A/C system is switched on, this relay permits the proper amount of current to pass through one of its line to activate this device.